Check the freon level...could be a tad bit low (R-134a is a much smaller molecule than R-22 thus is seeps out easier if there are old worn seals)
Also...at idle on a very hot day...might not be pulling enough air thru the condenser to adequately cool the freon and create the volume liquid to flow thru the expansion valve to cool enough (this also could mean it isn't compressing enough freon either...optimum compressor RPM's are around 2K)
Also check the fans/clutch assembly (if its a forward facing engine)/electric motors...if they are not coming on its not pulling air thru the condenser/radiator
Does your AC blow cold if you bump up the RPM's on the engine to around 2K (normal cruise speed on OD at 65mph) or not? Does it blow colder when you are cruising down the freeway vs sitting still?
97 degrees on the outside sitting in the sun = 140 on the inside, a closed vehicle sitting in the sun turns into an OVEN, always good to park in the shade or slightly crack the windows to allow the hot air to at least have someplace to go, or roll all your windows down for 5 minutes and let the latent convective heat escape before you try to cool 140 degree air to 60 degrees.
P.S. Welcome to Texas...where during the summer time, its no longer the closeness to the doors but the proximity of shade is the determining factor on where you park in the parking lot
P.S.S. Dark vinyl or pleather in the sun will practically bond with human skin if you wear shorts...I found out the hard way